feat: estimate tickets and see the team's velocity

Story points can be set on the ticket page and when creating a ticket,
and show on cards, column headers, subtasks and the backlog. The Sprints
tab charts the points finished per closed sprint and warns when a planned
sprint holds more than the recent average.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/web/tracker/infrastructure/src/lib/graphql/fragments.graphql

@@ -79,13 +79,13 @@ fragment IssueSummaryFields on Issue {
     title
   }
   rank
+  storyPoints
 }
 
 fragment IssueFields on Issue {
   ...IssueSummaryFields
   description
   figmaUrl
-  storyPoints
   dueDate
   createdAt
   allowedTransitions